Low immune function refers to an underactive and poor performing immune system. The immune system's prime function is to protect the body against infection and the development of cancer. Support and enhancement of the immune system is perhaps the most important step in achieving resistance to disease and reducing susceptibility to colds, flus, and cancer. Supporting the immune system involves a health-promoting lifestyle, stress management, exercise, diet, and the appropriate use of nutritional supplements and herbal medicines.

If you answer "yes" to any of the following questions, it is a sign that your immune system needs support:

Do you catch colds easily?

Do you get more than two colds a year?

Are you suffering chronic infection?

Do you get frequent cold sores or have genital herpes?

Are your lymph glands sore and swollen at times?

Do you have now or have you ever had cancer?

Recurrent or chronic infections -- even very mild colds -- only occur when the immune system is weakened. Under such circumstances, there is a repetitive cycle that makes it difficult to overcome the tendency toward infection: a weakened immune system leads to infection, infection causes damage to the immune system, which further weakens resistance. Enhancing the immune system can provide the answer to breaking the cycle.

What causes low immune function?

The health of the immune system is greatly impacted by a person's emotional state, level of stress, lifestyle, dietary habits and nutritional status. Nutrient deficiency is the most frequent cause of a depressed immune system. An overwhelming number of clinical and experimental studies indicate that any single nutrient deficiency can profoundly impair the immune system.

What dietary factors are important in low immune function?

Optimal immune function requires a healthy diet that is (1) rich in whole, natural foods, such as fruits, vegetables, whole grains, beans, seeds, and nuts, (2) low in fats and refined sugars, and (3) contains adequate, but not excessive, amounts of protein. On top of this, for optimal immune function, an individual should drink five or six 8-ounce glasses of water per day (preferably pure); take a high potency multivitamin-mineral supplement; engage in a regular exercise program of at least 30 minutes of aerobic exercise and 5 to 10 minutes of passive stretching daily; perform daily deep breathing and relaxation exercises; take time each day to play and enjoy family and friends; and still get at least 6 to 8 hours of sleep daily.

One of the more damaging food components to our immune system is sugar. In one study, the ingestion of 100 gram (roughly 3-1/2 ounces) portions of carbohydrate as glucose, fructose, sucrose, honey, and pasteurized orange juice all significantly reduced the ability of white blood cells (neutrophils) to engulf and destroy bacteria.

In contrast, the ingestion of 100 grams of starch had no effect. These effects started within less than 30 minutes after ingestion and lasted for over 5 hours. Typically, there was at least a 50 percent reduction in neutrophil activity two hours after ingestion. Since neutrophils constitute 60 to 70 percent of the total circulating white blood cells, impairment of their activity leads to depressed immunity.

Some of the most important food components to enhance immune function are the carotenes. Many of the immune-enhancing effects of carotenes, as well as other antioxidants, are due to their ability to protect the thymus gland from damage. The thymus is the major gland of our immune system. It is composed of two soft, pinkish-gray lobes lying in a bib-like fashion just below the thyroid gland and above the heart. The thymus gland shows maximum development immediately after birth.

During the aging process, the thymus gland undergoes a process of shrinkage or involution. The reason for this involution is that the thymus gland is extremely susceptible to free radical and oxidative damage caused by stress, drugs, radiation, infection, and chronic illness. When the thymus gland becomes damaged, its ability to control the immune system is severely compromised.

The thymus is responsible for many immune system functions, including the production of T lymphocytes, a type of white blood cell. The thymus gland also releases several hormones, such as thymosin, thymopoeitin, and serum thymic factor, which regulate many immune functions. Low levels of these hormones in the blood is associated with depressed immunity and an increased susceptibility to infection.

Typically, thymic hormone levels will be very low in the elderly; individuals prone to infection; cancer and AIDS patients; and when an individual is exposed to undue stress. Carotenes and other antioxidants may ensure optimal thymus gland activity by preventing damage to the thymus by free radicals and pro-oxidants.

Beyond protecting the thymus gland, carotenes have been shown to enhance the function of several types of white blood cells, as well as increase the antiviral and anticancer properties of our own immune system mediators, such as interferon. Simply stated, carotene-rich foods and drinks appear to be able to boost immunity.

Foods high in carotenes include colored vegetables, such as dark greens; yellow and orange squash, carrots, yams, and sweet potatoes; and red peppers and tomatoes. Also important for proper immune function, including protecting against cancer, is the inclusion of cabbage family vegetables (broccoli, Brussels sprouts, cabbages, cauliflower, collards, kale, and greens from mustard, radish and turnip), flavonoid rich berries, garlic and Jerusalem artichoke in the diet.

Yogurt has an ability to boost immune function, particularly when made with large amounts (billions per serving) of Bifidobacterium lactis. Consuming yogurt with Bifidobacterium lactis increases the proportions of total, helper, and activated T lymphocytes and natural killer cells. Other effects include an increase in immune cells' ability to phagocytize or engulf and destroy invaders as well as the tumor cell killing ability of their natural killer cells.

What nutritional supplements should I take for low immune function?

Foundation Supplements. There are three products that I think are critical in supporting good immune function:

A High Potency Multiple Vitamin and Mineral Formula

Vitamin D3: 2,000-5,000 IU/day

Fish oil: 1,000 to 3,000 mg EPA+DHA/day.

A high-potency multiple-vitamin and mineral formula is the first step in supporting the immune system with nutritional supplementation as it will address any underlying nutritional deficiencies. Deficiencies of virtually any nutrient can result in significantly impaired immune function especially deficiencies of vitamins C, E, A, B6, B12, and folic acid. Minerals that are especially important are zinc, iron, and selenium. In addition to a multiple, some specific nutrients are helpful in boosting immune function: vitamin C, vitamin E, and vitamin A.

Vitamin D3 is especially critical to immune health. Individuals who have vitamin D blood levels lower than 38 ng/ml had twice as many upper respiratory tract infections as those with higher levels. Clinical studies have validated vitamin D's ability to reduce the risk of colds and flu. To insure optimal vitamin D status, recently most health experts are advocating daily dosages of 2,000 to 5,000 IU.

Echinacea has been shown to exert significant effects on immune function in over 300 scientific investigations, not all of the clinical studies have been positive. Mixed results from clinical studies with Echinacea are most likely due to lack of or insufficient quantity of active compounds. Echinamide is a patented, clinically proven, product that guarantees high levels of the three key active groups of compounds responsible for echinacea's actions on the immune system. Follow label instructions.

Astragalus root (Astragalus membranaceus) is a traditional Chinese medicine used to treat viral infections including the common cold. Clinical studies in China have shown it to be effective when used as a preventive measure against the common cold. It has also been shown to reduce the duration and severity of symptoms in acute treatment of the common cold, as well as raise white blood cell counts in chronic leukopenia (a condition characterized by low white blood cell levels).

Research in animals indicates that astragalus apparently works by stimulating several factors of the immune system. In particular it appears to stimulate white blood cells to engulf and destroy invading organisms and cellular debris as well as enhance the production of interferon (a key natural compound produced by the body to fight viruses). Follow label instructions.

Wellmune is a special beta-glucan preparation from baker's yeast that has been shown to be effective in several double-blind studies in boosting immunity in preventing colds and the flu. Subjects were treated daily with either 500 mg of Wellmune or a placebo for 90 days. In one of these study results, the Wellmune group reported:

No missed work or school due to colds, compared with 1.38 days of work/school missed for the placebo group.

No incidence of fever, compared with 3.50 incidence in the placebo group.

An increase in quality of life, including physical energy and emotional well-being, as measured by a clinically validated health survey questionnaire.

Medicinal mushrooms like maitake, shitake, reishi, and cordyceps possess significant immune enhancing effects. Much of this activity is also due to the presence of beta-glucans. Numerous experimental and clinical studies have shown that mushroom beta-glucans activate white blood cells. Follow label instructions.

Probiotics refer to health-promoting bacteria products containing species like Lactobaccilli and Bifidobacter. These preparations can be valuable aids in boosting immunity. Take 6 to 12 billion live colony-forming units (CFU) daily.

Comment:

Our mood and attitude have a tremendous bearing on the function of our immune system. The bottom line is that when we are happy and optimistic, our immune system functions much better. Conversely, when we are depressed, our immune system tends to be depressed. When a person is under more stress or is depressed, they will need to make a conscious effort to boost their immune system -- that includes taking their supplements. It is not only major life stresses that can cause depressed immune function, but the more significant the stressor the greater the impact on the immune system. Negative emotions suppress immune function while positive emotions enhance immune function.

In my clinical practice, whenever patients are suffering from low immune function I will ask them who their favorite comedian is and then write a prescription for them to watch a movie or TV show that features that comedian. The bottom line is that if you want to have a healthy immune system, you need to laugh often.

How do I know if the recommendations are working?

Fewer colds and other virus infections, shorter bouts of infections, and better overall resistance to infections.